#include <stdio.h>

int main(){
	int result;
	char grade;
	printf("请输入你的成绩：\n");
	scanf("%d",&result);
	int r  = result - 50;
	r = r / 10;
	switch(r){
		case 5:
		case 4:
			grade = 'A';
			break;
		case 3:
			grade = 'B';
			break;
		case 2:
			grade = 'C';
			break;
		case 1:
			grade = 'D';
			break;
		default :	
			printf("哥们你不及格啊！！！");
	}
	printf("你的成绩是%c\n",grade);
}
